Re: [LINUX-KERNEL] C++ in linux kernel

2008-02-11 Thread vignesh babu bm 
http://www.vmware.com/download/server/open_source.html

On Feb 11, 2008 5:07 PM, rohit h <[EMAIL PROTECTED]> wrote:
>
> On Feb 8, 2008 9:24 PM, Jan Engelhardt <[EMAIL PROTECTED]> wrote:
> >
> > On Feb 9 2008 00:14, Joonwoo Park wrote:
> > >2008/2/8, rohit h <[EMAIL PROTECTED]>:
> > >> Hi,
> > >>  I am a kernel newbie.
> > >>  I tried to insmod a C++ module containing classes, inheritance.
> > >>  I am getting 'unresolved symbol' error when I use the 'new' keyword.
> > >>  What could the problem be?
> > >>
> > >>  What kind of runtime support is needed ( arm linux kernel)? Is a
> > >> patch available for it?
> > >>
> > >Please take a look at click modular router which is using c++ as a
> > >linux kernel module.
> > >http://www.read.cs.ucla.edu/click/
> > >The lib/glue.cc provides custom operator new.
> >
> > Uh, let's not make the world worse :)
> > Just call malloc from C++, and carefully select what C++ features
> > you are going to use. The VMware source for example does it right.
> >
>
> From the links given, I dig that following C++ features need runtime support:
>   a. Pure virtual functions
>   b. Global objects  : Needs compiler dependent changes
>   c. new & delete : Can use kmalloc / kfree instead
>   d. Run time type info
>   e. Exceptions
> I guess features d & e need considerable effort.
> Apart from these, am I free to use other C++ features?
> Where could I see the VMWare sources?
>
>
>
> > Compiling the kernel module with g++ is not a simple work, you may
> > need big patch for kernel itself.
>
> I don't want to compile entire kernel.
> I only want to compile my module with g++ and insmod it.
> Any hint on how to write the Makefile.
>
> Thanks in advance,
> Rohit
>
>
>
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Re: [LINUX-KERNEL] C++ in linux kernel

2008-02-11 Thread vignesh babu bm 
http://www.vmware.com/download/server/open_source.html

On Feb 11, 2008 5:07 PM, rohit h [EMAIL PROTECTED] wrote:

 On Feb 8, 2008 9:24 PM, Jan Engelhardt [EMAIL PROTECTED] wrote:
 
  On Feb 9 2008 00:14, Joonwoo Park wrote:
  2008/2/8, rohit h [EMAIL PROTECTED]:
   Hi,
I am a kernel newbie.
I tried to insmod a C++ module containing classes, inheritance.
I am getting 'unresolved symbol' error when I use the 'new' keyword.
What could the problem be?
  
What kind of runtime support is needed ( arm linux kernel)? Is a
   patch available for it?
  
  Please take a look at click modular router which is using c++ as a
  linux kernel module.
  http://www.read.cs.ucla.edu/click/
  The lib/glue.cc provides custom operator new.
 
  Uh, let's not make the world worse :)
  Just call malloc from C++, and carefully select what C++ features
  you are going to use. The VMware source for example does it right.
 

 From the links given, I dig that following C++ features need runtime support:
   a. Pure virtual functions
   b. Global objects  : Needs compiler dependent changes
   c. new  delete : Can use kmalloc / kfree instead
   d. Run time type info
   e. Exceptions
 I guess features d  e need considerable effort.
 Apart from these, am I free to use other C++ features?
 Where could I see the VMWare sources?



  Compiling the kernel module with g++ is not a simple work, you may
  need big patch for kernel itself.

 I don't want to compile entire kernel.
 I only want to compile my module with g++ and insmod it.
 Any hint on how to write the Makefile.

 Thanks in advance,
 Rohit



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Re: kmalloc() with size zero

2007-03-22 Thread Vignesh Babu BM 
On Fri, 2007-03-23 at 07:08 +0530, Jan Engelhardt wrote:
> 
> On Mar 22 2007 16:18, Stephane Eranian wrote:
> >
> I'd say "feature", glibc's malloc also returns an address on
> malloc(0).
> 
This is implementation defined-the standard allows for return of either
null or an address.
> 
> Jan
> --
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> 
> 
-- 
Regards,  
Vignesh Babu BM  
_  
"Why is it that every time I'm with you, makes me believe in magic?"
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Re: kmalloc() with size zero

2007-03-22 Thread Vignesh Babu BM 
On Fri, 2007-03-23 at 07:08 +0530, Jan Engelhardt wrote:
 
 On Mar 22 2007 16:18, Stephane Eranian wrote:
 
 I'd say feature, glibc's malloc also returns an address on
 malloc(0).
 
This is implementation defined-the standard allows for return of either
null or an address.
 
 Jan
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_  
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[KJ][PATCH] is_power_of_2 in fs/block_dev.c

2007-02-19 Thread Vignesh Babu BM 
Replacing (n & (n-1)) in the context of power of 2 checks
with is_power_of_2


Signed-off-by: vignesh babu <[EMAIL PROTECTED]>
--- 
diff --git a/fs/block_dev.c b/fs/block_dev.c
index fc7028b..e8f2a2b 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -22,6 +22,7 @@
 #include 
 #include 
 #include 
+#include 
 #include 
 #include "internal.h"
 
@@ -65,7 +66,7 @@ static void kill_bdev(struct block_device *bdev)
 int set_blocksize(struct block_device *bdev, int size)
 {
/* Size must be a power of two, and between 512 and PAGE_SIZE */
-   if (size > PAGE_SIZE || size < 512 || (size & (size-1)))
+   if (size > PAGE_SIZE || size < 512 || !is_power_of_2(size))
return -EINVAL;
 
/* Size cannot be smaller than the size supported by the device */

-- 
Regards,  
Vignesh Babu BM  
_  
"Why is it that every time I'm with you, makes me believe in magic?"
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[KJ][PATCH] is_power_of_2 in fat

2007-02-19 Thread Vignesh Babu BM 
Replacing (n & (n-1)) in the context of power of 2 checks
with is_power_of_2

Signed-off-by: vignesh babu <[EMAIL PROTECTED]>
--- 
diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index a9e4688..8437190 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -25,6 +25,7 @@
 #include 
 #include 
 #include 
+#include 
 #include 
 
 #ifndef CONFIG_FAT_DEFAULT_IOCHARSET
@@ -1216,8 +1217,7 @@ int fat_fill_super(struct super_block *sb, void *data, 
int silent,
}
logical_sector_size =
le16_to_cpu(get_unaligned((__le16 *)>sector_size));
-   if (!logical_sector_size
-   || (logical_sector_size & (logical_sector_size - 1))
+   if (!is_power_of_2(logical_sector_size)
|| (logical_sector_size < 512)
|| (PAGE_CACHE_SIZE < logical_sector_size)) {
if (!silent)
@@ -1227,8 +1227,7 @@ int fat_fill_super(struct super_block *sb, void *data, 
int silent,
goto out_invalid;
}
sbi->sec_per_clus = b->sec_per_clus;
-   if (!sbi->sec_per_clus
-   || (sbi->sec_per_clus & (sbi->sec_per_clus - 1))) {
+   if (!is_power_of_2(sbi->sec_per_clus)) {
if (!silent)
printk(KERN_ERR "FAT: bogus sectors per cluster %u\n",
       sbi->sec_per_clus);

-- 
Regards,  
Vignesh Babu BM  
_  
"Why is it that every time I'm with you, makes me believe in magic?"
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[KJ][PATCH] is_power_of_2 in fs/hfs

2007-02-19 Thread Vignesh Babu BM 
Replacing (n & (n-1)) in the context of power of 2 checks 
with is_power_of_2

Signed-off-by: vignesh babu <[EMAIL PROTECTED]>
--- 
diff --git a/fs/hfs/btree.c b/fs/hfs/btree.c
index 5fd0ed7..8a3a650 100644
--- a/fs/hfs/btree.c
+++ b/fs/hfs/btree.c
@@ -9,6 +9,7 @@
  */
 
 #include 
+#include 
 
 #include "btree.h"
 
@@ -76,7 +77,7 @@ struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 
id, btree_keycmp ke
tree->depth = be16_to_cpu(head->depth);
 
size = tree->node_size;
-   if (!size || size & (size - 1))
+   if (!is_power_of_2(size))
goto fail_page;
if (!tree->node_count)
goto fail_page;
diff --git a/fs/hfsplus/btree.c b/fs/hfsplus/btree.c
index a9b9e87..90ebab7 100644
--- a/fs/hfsplus/btree.c
+++ b/fs/hfsplus/btree.c
@@ -10,6 +10,7 @@
 
 #include 
 #include 
+#include 
 
 #include "hfsplus_fs.h"
 #include "hfsplus_raw.h"
@@ -69,7 +70,7 @@ struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 
id)
}
 
size = tree->node_size;
-   if (!size || size & (size - 1))
+   if (!is_power_of_2(size))
goto fail_page;
if (!tree->node_count)
goto fail_page;

-- 
Regards,  
Vignesh Babu BM  
_  
"Why is it that every time I'm with you, makes me believe in magic?"
-
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[KJ][PATCH] is_power_of_2 in fat

2007-02-19 Thread Vignesh Babu BM 
Replacing (n  (n-1)) in the context of power of 2 checks
with is_power_of_2

Signed-off-by: vignesh babu [EMAIL PROTECTED]
--- 
diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index a9e4688..8437190 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -25,6 +25,7 @@
 #include linux/parser.h
 #include linux/uio.h
 #include linux/writeback.h
+#include linux/log2.h
 #include asm/unaligned.h
 
 #ifndef CONFIG_FAT_DEFAULT_IOCHARSET
@@ -1216,8 +1217,7 @@ int fat_fill_super(struct super_block *sb, void *data, 
int silent,
}
logical_sector_size =
le16_to_cpu(get_unaligned((__le16 *)b-sector_size));
-   if (!logical_sector_size
-   || (logical_sector_size  (logical_sector_size - 1))
+   if (!is_power_of_2(logical_sector_size)
|| (logical_sector_size  512)
|| (PAGE_CACHE_SIZE  logical_sector_size)) {
if (!silent)
@@ -1227,8 +1227,7 @@ int fat_fill_super(struct super_block *sb, void *data, 
int silent,
goto out_invalid;
}
sbi-sec_per_clus = b-sec_per_clus;
-   if (!sbi-sec_per_clus
-   || (sbi-sec_per_clus  (sbi-sec_per_clus - 1))) {
+   if (!is_power_of_2(sbi-sec_per_clus)) {
if (!silent)
printk(KERN_ERR FAT: bogus sectors per cluster %u\n,
   sbi-sec_per_clus);

-- 
Regards,  
Vignesh Babu BM  
_  
Why is it that every time I'm with you, makes me believe in magic?
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[KJ][PATCH] is_power_of_2 in fs/hfs

2007-02-19 Thread Vignesh Babu BM 
Replacing (n  (n-1)) in the context of power of 2 checks 
with is_power_of_2

Signed-off-by: vignesh babu [EMAIL PROTECTED]
--- 
diff --git a/fs/hfs/btree.c b/fs/hfs/btree.c
index 5fd0ed7..8a3a650 100644
--- a/fs/hfs/btree.c
+++ b/fs/hfs/btree.c
@@ -9,6 +9,7 @@
  */
 
 #include linux/pagemap.h
+#include linux/log2.h
 
 #include btree.h
 
@@ -76,7 +77,7 @@ struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 
id, btree_keycmp ke
tree-depth = be16_to_cpu(head-depth);
 
size = tree-node_size;
-   if (!size || size  (size - 1))
+   if (!is_power_of_2(size))
goto fail_page;
if (!tree-node_count)
goto fail_page;
diff --git a/fs/hfsplus/btree.c b/fs/hfsplus/btree.c
index a9b9e87..90ebab7 100644
--- a/fs/hfsplus/btree.c
+++ b/fs/hfsplus/btree.c
@@ -10,6 +10,7 @@
 
 #include linux/slab.h
 #include linux/pagemap.h
+#include linux/log2.h
 
 #include hfsplus_fs.h
 #include hfsplus_raw.h
@@ -69,7 +70,7 @@ struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 
id)
}
 
size = tree-node_size;
-   if (!size || size  (size - 1))
+   if (!is_power_of_2(size))
goto fail_page;
if (!tree-node_count)
goto fail_page;

-- 
Regards,  
Vignesh Babu BM  
_  
Why is it that every time I'm with you, makes me believe in magic?
-
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[KJ][PATCH] is_power_of_2 in fs/block_dev.c

2007-02-19 Thread Vignesh Babu BM 
Replacing (n  (n-1)) in the context of power of 2 checks
with is_power_of_2


Signed-off-by: vignesh babu [EMAIL PROTECTED]
--- 
diff --git a/fs/block_dev.c b/fs/block_dev.c
index fc7028b..e8f2a2b 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -22,6 +22,7 @@
 #include linux/mount.h
 #include linux/uio.h
 #include linux/namei.h
+#include linux/log2.h
 #include asm/uaccess.h
 #include internal.h
 
@@ -65,7 +66,7 @@ static void kill_bdev(struct block_device *bdev)
 int set_blocksize(struct block_device *bdev, int size)
 {
/* Size must be a power of two, and between 512 and PAGE_SIZE */
-   if (size  PAGE_SIZE || size  512 || (size  (size-1)))
+   if (size  PAGE_SIZE || size  512 || !is_power_of_2(size))
return -EINVAL;
 
/* Size cannot be smaller than the size supported by the device */

-- 
Regards,  
Vignesh Babu BM  
_  
Why is it that every time I'm with you, makes me believe in magic?
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[KJ][PATCH] is_power_of_2 in ia64mm

2007-02-16 Thread Vignesh Babu BM 
Replacing (n & (n-1)) in the context of power of 2 checks
with is_power_of_2


diff --git a/arch/ia64/mm/hugetlbpage.c b/arch/ia64/mm/hugetlbpage.c
index 0c7e94e..0ccc70e 100644
--- a/arch/ia64/mm/hugetlbpage.c
+++ b/arch/ia64/mm/hugetlbpage.c
@@ -16,6 +16,7 @@
 #include 
 #include 
 #include 
+#include 
 #include 
 #include 
 #include 
@@ -175,7 +176,7 @@ static int __init hugetlb_setup_sz(char *str)
tr_pages = 0x15557000UL;
 
size = memparse(str, );
-   if (*str || (size & (size-1)) || !(tr_pages & size) ||
+   if (*str || !is_power_of_2(size) || !(tr_pages & size) ||
size <= PAGE_SIZE ||
size >= (1UL << PAGE_SHIFT << MAX_ORDER)) {
printk(KERN_WARNING "Invalid huge page size specified\n");

-- 
Regards,  
Vignesh Babu BM  
_  
"Why is it that every time I'm with you, makes me believe in magic?"
-
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[KJ][PATCH] is_power_of_2 in ia64mm

2007-02-16 Thread Vignesh Babu BM 
Replacing (n  (n-1)) in the context of power of 2 checks
with is_power_of_2


diff --git a/arch/ia64/mm/hugetlbpage.c b/arch/ia64/mm/hugetlbpage.c
index 0c7e94e..0ccc70e 100644
--- a/arch/ia64/mm/hugetlbpage.c
+++ b/arch/ia64/mm/hugetlbpage.c
@@ -16,6 +16,7 @@
 #include linux/smp_lock.h
 #include linux/slab.h
 #include linux/sysctl.h
+#include linux/log2.h
 #include asm/mman.h
 #include asm/pgalloc.h
 #include asm/tlb.h
@@ -175,7 +176,7 @@ static int __init hugetlb_setup_sz(char *str)
tr_pages = 0x15557000UL;
 
size = memparse(str, str);
-   if (*str || (size  (size-1)) || !(tr_pages  size) ||
+   if (*str || !is_power_of_2(size) || !(tr_pages  size) ||
size = PAGE_SIZE ||
size = (1UL  PAGE_SHIFT  MAX_ORDER)) {
printk(KERN_WARNING Invalid huge page size specified\n);

-- 
Regards,  
Vignesh Babu BM  
_  
Why is it that every time I'm with you, makes me believe in magic?
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